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Adsorption of Pb(II) Ions from Aqueous Solutions by Date Bead Carbon Activated with ZnCl 2
Author(s) -
Danish Mohammed,
Hashim Rokiah,
Rafatullah Mohd,
Sulaiman Othman,
Ahmad Anees
Publication year - 2011
Publication title -
clean – soil, air, water
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 66
eISSN - 1863-0669
pISSN - 1863-0650
DOI - 10.1002/clen.201000185
Subject(s) - adsorption , endothermic process , gibbs free energy , enthalpy , chemistry , aqueous solution , freundlich equation , activated carbon , thermodynamics , standard molar entropy , langmuir adsorption model , langmuir , physics
This study reports on the adsorption characteristics of Pb(II) ions from aqueous solutions using ZnCl 2 ‐activated date ( Phoenix dactylifera ) bead (ADB) carbon with respect to change in adsorbent dosage, initial pH, contact time, initial concentration, and temperature of the solution. Kinetic studies of the data showed that the adsorption follows the pseudo‐second‐order kinetic model. Thermodynamic parameters, enthalpy change (Δ H ° = 55.11 kJ/mol), entropy change (Δ S ° = − 0.193 kJ/mol/K), and Gibbs free energy change (Δ G °) were also calculated for the uptake of Pb(II) ions. These parameters show that adsorption on the surface of ADB was feasible, spontaneous in nature, and endothermic between temperatures of 298.2 and 318.2 K. The equilibrium data better fitted the Langmuir and Freundlich isotherm models than the D–R adsorption isotherm model for studying the adsorption behavior of Pb(II) onto the ADB carbon. It could be observed that the maximum adsorption capacity of ADB was 76.92 mg/g at 318.2 K and pH 6.5.